1. Field of the Invention
The present invention relates to a method for manufacturing a corrugated fin that is disposed and used in a heat exchanger such as a radiator and a heater core.
2. Description of the Related Art
Conventionally, in a heat exchanger such as a radiator and a heater core, a corrugated fin is interposed between tubes to thereby enhance the heat radiating performance of the heat exchanger.
Recently, as a corrugated fin of this type, as shown in FIG. 9, there has been developed a corrugated fin 1 which has a rectangular-shaped corrugated shape.
In the corrugated fin 1, since the bent portions 1a thereof are formed to be flat, the brazing strength of the corrugated fin 1 to the tube can be enhanced.
Conventionally, to manufacture the corrugated fin 1, as shown in FIG. 10, a long plate member 3 is continuously supplied between a pair of corrugated cutters 2a and 2b to thereby form a corrugated fin 4.
FIG. 13 shows an enlarged view of the pair of corrugated cutters 2. The pair of corrugated cutters 2 are an upper corrugated cutter 2a and a lower corrugated cutter 2b, each formed in a cylindrical shape. A plurality of protrusions and recesses are formed on the surface of each of the upper and lower corrugated cutters 2a and 2b, and the plurality of protrusions and recesses of the upper and lower corrugated cutters 2a and 2b are alternatively engaged with each other as the upper and lower corrugated cutters 2a and 2b rotate.
FIG. 14 is a sectional view taken along a line Axe2x80x94A in FIG. 13, and shows a pair of teeth in the engaging portion of the pair of corrugated cutters 2a and 2b. FIG. 15 is an enlarged view of FIG. 14. Along with the shapes of the teeth, the pair of corrugated cutters 2a and 2b partly cut inclined portions 4b to define cut portions, and bend the cut portions toward the advancing direction of the long plate member to form a plurality of louvers 7 in the inclined portions 4b of the corrugated fin 4. FIG. 12 shows the louvers 7 that are cut and bent by the cutters 2a and 2b. The louvers 7 include one-side louvers 7a and 7b formed at both ends of a central portion 4c and projected to the opposing direction to the advancing direction, one-side louvers 7e and 7f formed at ends of both side portions 4e in the inclined portions 4b and projected to the advancing direction, and a plurality of louvers 7c and 7d formed between the one-side louvers 7a and 7b and the one-side louvers 7e and 7f, respectively.
Then, the thus formed corrugated fin 4 is moved by a pair of feed-out rollers 5. And, the corrugated fin 4 is passed through and between pairs of flick-out plates 6 and is passed through a pitch adjuster, which is not shown, disposed adjacent to the pairs of flick-out plates 6 in the downstream side. The pairs of flick-out plates 6 certainly remove the corrugated fin 4 from the feed-out rollers 5 and adjust the height of each fin of the corrugated fin 4 and the pitch adjuster adjusts the fin pitch of the corrugated fin 4.
That is, in the corrugated fin 4 formed by the pair of corrugated cutters 2a and 2b, the flat-shaped bent portion 4a and the inclined portion 4b are alternatively formed so that the corrugated fin 4 has a trapezoidal shape. Then, the corrugated fin 4 is passed through the pairs of flick-out plates 6 and the pitch adjuster to thereby transform the trapezoidal shape of the corrugated fin 4 into a rectangular shape.
However, in the conventional manufacturing method, there is found a problem that the corrugated fin 1 is caught between the pairs of flick-out plates 6.
The present invention is made to solve the above-mentioned problem. Accordingly, it is an object of the invention to provide a method for manufacturing a corrugated fin, which, when compared with the above-mentioned conventional corrugated fin manufacturing method, can greatly reduce a fear that the corrugated fin can be caught between pairs of flick-out plates.
In attaining the above object, according to the invention, there is provided a method for manufacturing a corrugated fin, in which a long plate member is continuously supplied into between a pair of corrugated cutters to thereby form a corrugated fin having a bent portion formed as a flat-shaped bent portion and including a plurality of louvers formed in the width direction of an inclined portion of the corrugated fin and, after then, the thus formed corrugated fin is passed through between pairs of flick-out plates disposed at positions respectively corresponding to the two width-direction end portions of the flat-shaped bent portion, thereby not only reducing the fin pitch of the corrugated fin but also transforming the shape of the corrugated fin to a shape in which the flat-shaped bent portion extends in parallel to the advancing direction of the corrugated fin. The plurality of louvers are formed symmetrically on the two sides of the width-direction central portion of the inclined portion, one-side louvers, which are formed integrally in one and the other ends of the central portion, are formed so as to project from one and the other ends of the central portion of the inclined portion toward the advancing direction of the corrugated fin, and louvers, which are formed respectively on one and the other sides of the central portion, are formed inclined on the same sides as the one-side louvers that are formed in one and the other ends of the central portion of the inclined portion.
In a method for manufacturing a corrugated fin according to the invention, as described above, the plurality of louvers are formed symmetrically on the two sides of the width-direction central portion 15c of the inclined portion, one side louvers, which are formed integrally in one and the other ends of the central portion of the inclined portion, are formed so as to project from one and the other ends of the above-mentioned central portion toward the advancing direction of the corrugated fin, and louvers, which are formed on one and the other sides of the above central portion, are formed inclined on the same sides as the one-side louvers that are formed in one and the other ends of the central portion. Thanks to this, in case where the corrugated fin is passed through between the pairs of flick-out plates disposed at positions respectively corresponding to the two width-direction end portions of the flat-shaped bent portion of the corrugated fin to thereby reduce the fin pitch of the corrugated fin, the two width-direction end portions of the flat-shaped bent portion of the corrugated fin are inclined forwardly, thereby being able to transform the shaped of the corrugated fin into a rectangular shape.